Hybrid Fiber Coax (HFC) cable networks were originally built to deliver broadcast-quality TV signals to homes. The wide availability of such systems and the extremely wide bandwidth of these systems led to the extension of their functionality to include delivery of high-speed broadband data signals to end-users. Data over Cable System Interface Specifications (DOCSIS), a protocol elaborated under the leadership of Cable Television Laboratories, Inc., has been established as the major industry standard for two-way communications over HFC cable plants.
The basic elements of a DOCSIS-compliant cable network are the cable modem (CM), located on the subscriber's site, and the cable modem termination system (CMTS) and head end located in facilities operated by the cable service provider. The medium between the CMTS and the different CMs is a two-way shared medium, in which the downstream channels carry signals from the head-end to users and upstream channels carry signals from users to head-end. A CM is normally tuned to one upstream channel and the associated downstream channel. The upstream channel is an inherently shared medium in which slots are reserved using a contention system while the downstream is a broadcast dedicated link from the CMTS to the CM.
In recent years, packet-switched networks, such as the Internet, wireless communication, ADSL and CATV, have become more widespread. Packet-switched networks, such as networks based on the TCP/IP protocol suite, can distribute a rich array of digital content to a variety of client applications. It is often advantageous when distributing digital content across a packet-switched network to provide a distributed system that includes a plurality of servers dispersed throughout the distribution network, wherein the content is mirrored on the distributed servers. A more recent alternative to mirroring is content distribution networks (CDNs) that dynamically redirect content requests to an edge server situated closer to the client issuing the request.
As IP or packet-based solutions for providing content increases, the infrastructure for distributing content and services will be changing. For example, the infrastructure may need to evolve to support additional devices or different types of devices. Even for supporting set-top boxes, a different infrastructure may be used than that currently implemented.
Today, most content is maintained at a centralized backoffice server, i.e., at the corporate level rather than in the network. For example, in the cable industry there are many different systems and/or service areas that are supported. The centralized location provides broad access for all subscribers. Thus, the central server services several content delivery networks (CDNs).
The CDN serve as relay servers located in respective regions, wherein the edge servers store a content that includes favorites of users. Thereby, by accessing the edge servers without directly accessing the archive server, the users may be able to download favorite content in a relatively short time. Although the edge servers store relatively popular content, the edge servers may not match actual users' preferences, in which case the users may have to directly access the archive server. Repeated occurrence of such a situation would increase the load on the archive server, make it difficult to maintain a given service quality, and lose opportunities to provide services for customers.